1. Field of the Invention
The present invention relates to a recording apparatus, a conveyance device, and a conveyance control method.
2. Description of the Related Art
In recording apparatuses (printers), there are known automatic sheet feeders of the type that sheets are held in a substantially horizontally stacked state under a main body of the recording apparatus and are fed one by one (e.g., Japanese Patent Laid-Open No. 2005-8416), and of the type that sheets are held in an obliquely stacked state on the rear side of the recording apparatus and are fed one by one. Some of recording apparatuses includes both the types of automatic sheet feeders.
Further, there is known a method of performing the so-called U-turn sheet feed by holding recording sheets in a substantially horizontally stacked state under the main body of the recording apparatus and conveying the recording sheets one by one along a cylindrical concave surface for feed of the sheet. Such a sheet feed mode is suitable for feeding a thin sheet made of plain paper, for example.
The U-turn sheet feed mode has a longer conveying path than the other mode of holding sheets in an obliquely stacked state on the rear side of the recording apparatus and feeding the sheets one by one, and is more apt to cause a sheet jam in the conveying path. Therefore, the U-turn sheet feed mode requires a sheet detecting sensor which is disposed in the conveying path.
Further, in a sheet feed unit utilizing a swing arm, when a pickup operation by a pickup roller (sheet feed roller) is performed without setting of printing sheets (i.e., with no printing sheets placed in a tray), the swing arm comes into contact with the tray, thus resulting in a state that the sheet feed roller is not rotated (namely, it is locked).
At that time, a control system for controlling a motor, which serves as a roller driving source, falsely detects the occurrence of an error state. To avoid such a false detection, a driven roller for escaping a pressing force applied to the pickup roller is required to be disposed just below the pickup roller.